System and method to improve performance of a compressor device comprising variable diffuser vanes

ABSTRACT

Embodiments of a system and method can modify the position of diffuser vanes to improve performance of a compressor device, e.g., a centrifugal compressor. These embodiments form a feedback loop to manage the position of the diffuser vanes relative to one or more operating parameters on the compressor device. In one embodiment, the system and method measure input power with the diffuser vanes at a first position and a second position. Changes in the input power will identify other positions for the diffuser vanes that optimize performance of the compressor device, e.g., to reduce power consumption and to achieve and maintain peak compressor efficiency within the entire operating envelope of the compressor device.

BACKGROUND

The subject matter disclosed herein relates to compressor devices (e.g., centrifugal compressors) and, in particular, to diffusers and diffuser vanes for a compressor device.

Compressor devices (e.g., centrifugal compressors) use a diffuser assembly to convert kinetic energy of a working fluid into static pressure by slowing the velocity of the working fluid through an expanding volume region. An example of the diffuser assembly utilizes several diffuser vanes in circumferential arrangement about an impeller. The design (e.g., shapes and sizes) of the diffuser vanes, in combination with the orientation of the leading edge and the trailing edge of the diffuser vanes with respect to the flow of the working fluid, often determine how the diffuser vanes affix within the diffuser assembly.

To add further improvement and flexibility to the design, some examples of the diffuser assembly incorporate variable diffuser vanes. These types of diffuser vanes can move to change the orientation of the leading edge and the trailing edge. This feature helps to tune operation of the compressor device. Known designs for variable diffuser vanes rotate about an axis that resides in the lower half of the diffuser vanes, i.e., closer to the leading edge than the trailing edge.

BRIEF DESCRIPTION OF THE INVENTION

This disclosure presents embodiments of systems and methods that can modify orientation of variable diffuser vanes to improve performance of a compressor device, e.g., a centrifugal compressor. These embodiments form a control feedback loop to manage the position of the diffuser vanes relative to one or more operating parameters on the compressor device. In one embodiment, the system utilizes a controller to collect data about operating parameter(s) for the diffuser vanes in a first position and a second position. The controller can compare data to identify the change, if any, that occurs in the operating parameter when the diffuser vanes move between the first position and the second position. In one embodiment, changes in the operating parameter can cause the controller to generate an output to move the diffuser vane to a third position. The controller can collect data about the operating parameter(s) at this third position and, subsequently, use this data to determine to effect the new position of the diffuser vanes has on the operating parameter. This process can continue to optimize performance of the compressor device, e.g., to reduce power consumption and to achieve and maintain peak compressor efficiency within the entire operating envelope for the compressor device.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made briefly to the accompanying drawings, in which:

FIG. 1 depicts a front, perspective view of an example of a compressor device;

FIG. 2 depicts a back, perspective view of the compressor device of FIG. 1;

FIG. 3 depicts a schematic diagram of an exemplary embodiment of a system for controlling operation of a compressor device, e.g., the compressor device of FIGS. 1 and 2;

FIG. 4 depicts a flow diagram of an exemplary embodiment of a method for operating a compressor device, e.g., the compressor device of FIGS. 1 and 2;

FIG. 5 depicts a top view of the exemplary diffuser vane in a first position and a second position for use in a compressor device, e.g., the compressor device of FIGS. 1 and 2;

FIG. 6 depicts a top view of the exemplary diffuser vane of FIG. 5 in a first position, a second position, and a third position; and

FIG. 7 depicts a high-level wiring schematic of an example of controller for use in a system, e.g., the system of FIG. 3.

Where applicable like reference characters designate identical or corresponding components and units throughout the several views, which are not to scale unless otherwise indicated.

DETAILED DESCRIPTION OF THE INVENTION

Broadly, the discussion below focuses on embodiments of systems and methods to manage the position of diffuser vanes in a compressor device, e.g., a centrifugal compressor. These embodiments offer a robust and automated approach to tune operation of the compressor device. In one aspect, these embodiments can manipulate the position of the diffuser vanes to reduce power consumption of the compressor device. This feature can help to achieve and maintain peak efficiency within the entire operating envelope of the compressor device.

FIGS. 1 and 2 depict an example of a compressor device 100. In FIG. 1, the compressor device 100 has an inlet 102 and a volute 104 that forms an outlet 106. A drive unit 108 couples to an impeller 110. As best shown in FIG. 2, the compressor device 100 includes a diffuser assembly 112 with a plurality of diffuser vanes 114. The volute 104 forms an interior diffuser cavity that surrounds the diffuser vanes 114. The diffuser assembly 112 also includes an actuator 116, which couples to the diffuser vanes 114 to change the position of the diffuser vanes 114 as set forth herein.

During operation, the drive unit 108 rotates the impeller 110 to draw a working fluid (e.g., air) into the inlet 102. The impeller 110 compresses the working fluid. The compressed working fluid flows into the diffuser assembly 112, past the diffuser vanes 114, and through the remaining portion of the volute 104. In one embodiment, the compressor device 100 couples with industrial piping at the outlet 106 to expel the working fluid under pressure and/or with certain designated flow parameters as desired. For example, the compressor device 100 finds use in a variety of settings and industries including automotive industries, electronics industries, aerospace industries, oil and gas industries, power generation industries, petrochemical industries, and the like.

FIG. 3 illustrates a schematic diagram of a system 118 for controlling operation of the compressor device 100. The system 118 includes a controller 120 and a parameter sensor 122. The controller 120 communicates with the drive unit 108 to control rotation of the impeller 110. The controller 120 can also communicate with the diffuser assembly (e.g., diffuser assembly 112 of FIG. 2) by communicating with the actuator 116 to cause the diffuser vanes 114 to change position, e.g., from a first position to a second position. In one embodiment, the controller 120 (or one or more other devices in the system 118) can communicate via a network 124 with a peripheral device 126 (e.g., a display, a computer, smartphone, laptop, tablet, etc.) and/or an external server 128.

Examples of the controller 120 include computers and computing devices with processors and memory that can store and execute certain executable instructions, software programs, and the like. The controller 120 can be a separate unit, e.g., part of a control unit that operates the compressor device 100 and other equipment. In other examples, the controller 120 integrates with the compressor device 100, e.g., as part of the hardware and/or software that operates the drive unit 108 and/or the actuator 116. In still other examples, the controller 120 can be located remote from the compressor device 100, e.g., in a separate location. The controller 120 can issue commands and instructions using wireless and wired communication, e.g., via the network 124.

The parameter sensor 122 monitors one or more operating parameters of the compressor device 100. Examples of these operating parameters include flow parameters (e.g., flow rate, flow velocity, static pressure, head pressure, etc.) and mechanical parameters (e.g., input power, current, voltage, torque, etc.), among others. The parameter sensor 122 can comprise one or more sensor devices that are sensitive to the operating parameters. These sensor devices can embody flow meters, pressure transducers, accelerometers, and like components. Such devices generate signals (e.g., analog and digital signals), which encode a measured value for the corresponding operating parameter that the device is configured to measure.

The parameter sensor 122 may also couple with a shaft or other mechanism that transfers energy from the drive unit 108 to the impeller 110. When in this position, the parameter sensor 122 can measure several parameters (e.g., torque, angular velocity, etc.) that define the operation of the drive unit 108 and/or the compressor device 102 in general. Other positions for the parameter sensor 122 include proximate the interior of the volute 104, proximate the outlet 106, proximate the diffuser assembly (e.g., diffuser assembly 112 of FIG. 2) as well as other positions to measure flow parameters as the working fluid moves through the compressor device 100. Moreover, the compressor device 100 may include circuitry to operate the drive unit 108 that includes certain configurations of elements (e.g., capacitors, resistors, transistors, etc.) to monitor inputs to the drive unit 108, e.g., current, voltage, power, etc.

Embodiments of the system 118 can include a plurality of sensor devices (e.g., parameter sensor 122) that measure different operating parameters. For example, the system 118 may deploy a flow meter upstream of the diffuser vanes 114, a pressure sensor proximate the outlet 106, and/or circuitry to monitor the amount of power the drive unit 108 uses during operation of the compressor device 100. The sensor devices provide signals to the controller 120. These signals transmit and/or encode data and information about the operation of the compressor device 100. The controller 120 can process the signals from the sensor devices to generate the outputs. These outputs can encode instructions for operation of one or more components to configure the compressor device 100. As set forth more below, the outputs can encode instructions to change the position of the diffuser vanes 114, e.g., to instruct operation of the actuator 116 to change the orientation and/or position of one or more of the diffuser vanes 114. These instructions may, for example, cause the actuator 116 to move, which, in turn, moves (e.g., rotates) the diffuser vanes 114 through an angular offset from the first position to the second position.

FIG. 4 illustrates a flow diagram of an exemplary embodiment of a method 200 to operate a compressor device (e.g., compressor device 100 of FIGS. 1, 2, and 3). The method 200 includes, at step 202, receiving a first signal that encodes a first value for an operating parameter with the diffuser vane in a first position and, at step 204, receiving a second signal that encodes a second value for the operating parameter with the diffuser vane in a second position. The method 200 also includes, at step 206, comparing the first value and the second value. The method 200 further includes, at step 208, selecting an increment by which to move the diffuser vanes and, at step 210, generating an output that encodes information to move the diffuser vane from the second position by the increment.

Collectively, one or more of the steps of the method 200 can be coded as one or more executable instructions (e.g., hardware, firmware, software, software programs, etc.). These executable instructions can be part of a computer-implemented method and/or program, which can be executed by a processor and/or processing device. Examples of the controller 120 (FIG. 3) can execute these executable instruction to generate certain outputs, e.g., a signal that encodes instructions to change the position of the diffuser vanes 114 (FIGS. 1, 2, and 3), a signal that encodes instructions to change operation of the drive unit 108 (FIGS. 1, 2, and 3), etc.

The steps for receiving a first signal (e.g., at step 202) and a second signal (e.g., a step 204) occur at different positions of the diffuser vanes 114 (FIGS. 2 and 3) to capture potential changes in operation of the compressor device 100 (FIGS. 1, 2, and 3). To illustrate, FIG. 5 shows an example of a diffuser vane 300 in a first position 302 and a second position, identified by phantom lines and the numeral 304. In one embodiment, the diffuser vane 300 changes between the first position 302 and the second position 304 in response to operation of a linear actuator (e.g., actuator 116 of FIG. 3).

The diffuser vane 300 has a vane body 306 with a leading edge 308 and a trailing edge 310. The diffuser vane 300 rotates about a rotation axis 312 to permit changes in the position of the trailing edge 310 relative to, in one example, the leading edge 308. This disclosure also contemplates construction of the diffuser vane 300 that would allow both the leading edge 308 and the trailing edge 310 to move about the rotation axis 312. For example, the rotation axis 312 can be positioned at various locations along the vane body 306, e.g., in locations spaced apart from the leading edge 308 and the trailing edge 310 along a chord length L. The chord length L measures the straight-line distance between the leading edge 308 and the trailing edge 310.

With respect to the configuration of the diffuser vane 300 in FIG. 5, rotation about the leading edge 308 is advantageous to accommodate the direction of the flow F, which can change orientation e.g., from a first flow direction F1 to a second flow direction F2. To this end, despite the relatively large angular displacement of the trailing edge 310 that occurs, the leading edge 308 is secured on the rotation axis 312 to limit changes to the position of the leading edge 308 as the trailing edge 310 moves between the first position 302 and the second position 304. This feature maintains the orientation of the leading edge 308 with the second flow F2 to reduce the likelihood of flow separation, while providing adequate adjustment of the trailing edge 310 to dictate changes in the performance, e.g., of the compressor device 100 (FIGS. 1, 2, and 3).

Communication of the first signal and the second signal can occur by way of wireless and/or wired communication, e.g., between the parameter sensor 122 (FIGS. 1, 2, and 3) and the controller 120 (FIG. 3). The signal encodes information about the operating parameters for the compressor device 100 (FIGS. 1, 2, and 3). This information includes values (also “measured values”) that may reflect a quantity (e.g., meters/second, Hz, etc.) or other determinant values (e.g., voltage level, current level, power, etc.) that can define the operating parameter under measurement. In one embodiment, the method 200 can includes steps for receiving a plurality of signals from different sensor devices and for selecting one or more of the signals based on, for example, the type of information and data the signals encode. These features of the method 200 can permit the selection of particular information, e.g., flow rate of incoming working fluid upstream of the diffuser vanes 114 (FIGS. 1, 2, and 3), and/or combinations of information, e.g., flow rate of incoming working fluid upstream of the diffuser vanes 114 (FIGS. 1, 2, and 3), pressure at the outlet 106 (FIGS. 1 and 2), and power consumption at the drive unit 108. These selections may be part of a user interface (e.g., a graphical user interface) that displays on one or more of the peripheral devices 126 (FIG. 3) or on other display equipment associated with the compressor device 100 (FIGS. 1, 2, and 3) and/or the system 118 (FIG. 3).

The steps for comparing the first value and the second value (e.g., a step 206) identifies the change or variation in operation of the compressor device 100 (FIGS. 1, 2, and 3) that corresponds with the change in position of the diffuser vane 300. These changes can, for example, increase and/or decrease the operating parameter. For purpose of one example, this comparison captures the relative change in input power (or power consumption) of the drive unit 108 (FIGS. 1, 2, and 3) that occurs when the diffuser vane 300 moves from the first position 302 to the second position 304.

The steps for selecting an increment (e.g., at step 208) provides an incremental change in the position of the diffuser vanes 300. This incremental change is meant to move the diffuser vanes 300 to another position in order to change the performance of the compressor device 100 (FIGS. 1, 2, and 3). Examples of the incremental change can define both the amount of movement that will occur in the diffuser vane 300 as well as the direction of movement. FIG. 6, for example, illustrates the diffuser vane 300 in a third position 314, which represents the position of the diffuser vane 300 offset from the second position 302 by an increment 316. As shown in the example of FIG. 6, the increment 316 defines several positional characteristics (e.g., an angular offset 318 and a direction 320) that determine the extent to which the position of the diffuser vane 300 changes relative to the second position 304. In one embodiment, the method 200 can include steps for comparing the relative values of the first value and the second value to assign the positional characteristics. For example, if the second value is less than the first value, then the method 200 can include steps for assigning the increment 316 a first set of positional characteristics that comprise a first direction and a first angular offset. On the other hand, if the second value is less than the first value, then the method 200 can include steps for assigning the increment 316 a second set of positional characteristics that comprise a second direction and a second angular offset. In one example, the first direction is different from the second direction (e.g., with respect of FIG. 6, the first direction is clockwise and the second direction is counter clockwise).

The amount of the angular offset can vary, both between the first angular offset and the second angular offset as well as based on the first value and the second value for the operating parameter. For example, embodiments of the method 200 may include steps for calculating a variation value, which can have a value equal to the mathematical difference between the first value and the second value, and a step for comparing the variation value to a threshold criteria that can define the nominal values for the positional characteristics. In one example, if the variation value satisfies the threshold criteria, then the method 200 may includes steps for assigning values to the increment 316. These values may decrease as the variation value decreases, e.g., as the operation of the compressor device 100 (FIGS. 1, 2, and 3) converges to an optimal set of operating settings (e.g., optimal position for the diffuser vanes).

The steps for generating an output (e.g., at step 210) can cause the diffuser vane 300 to move, as between the second position 304 and the third position 314. The output can comprise any signal (e.g., analog and/or digital) that can encode instructions to operate a device. In the examples herein, the output can cause the actuator 116 (FIGS. 1, 2, and 3) to move, which can facilitate movement either directly and/or indirectly of the diffuser vanes (e.g., diffuser vanes 114 of FIGS. 2 and 3 and/or diffuser vane 300 of FIGS. 5 and 6) among and between one or more of the first position 302, the second position 304, and the third position 314.

In view of the foregoing discussion of the method 200, this disclosure contemplates embodiments in which the method 200 embodies an iterative and/or multi-operational technique to focus and optimize operation, e.g., of the compressor device 100 (FIGS. 1, 2, and 3). To this end, the method 200 may include one or more steps for resetting and or initializing one or more values for the operating parameter (e.g., the first value and the second value) and the positional characteristics. This feature prepares the methodology to accept additional data and/or to operate in a manner that promotes incremental changes in the position of the diffuser vanes (e.g., diffuser vanes 114 of FIGS. 1, 2, and 3 and diffuser vane 300 of FIGS. 5 and 6). For example, in one embodiment, on a second “pass” through the method 200, the first value from the operating parameter may be assigned the second value and, in turn, the second value may comprise a new value that identifies the operating value that occurs after the diffuser vane changes from the second position to the third position. In this way, the method 200 can compare at least one previous value to a new value for purposes of iterating the methodology to an optimum solution. For purposes of such an example, it may be unnecessary to receive and/or decode both the first signal (e.g., at step 202), but rather supplement the steps of the method 200 with one or more steps for assigning the first value with the second value, initializing the second value, and continuing on to receiving the second signal (e.g., at step 204).

FIG. 7 depicts a schematic diagram that presents, at a high level, a wiring schematic for a controller 400 that can process data (e.g., signals) to generate an output that instructs operation of a compressor device (e.g., compressor device 100 of FIGS. 1, 2, and 3). The controller 400 can be incorporated as part of a compressor device to provide an integrated and effective stand-alone system. In other alternatives, the controller 400 can remain separate and/or as part of a control system, which can also monitor various operations of the compressor device as well as the systems coupled thereto.

In one embodiment, the controller 400 includes a processor 402, memory 404, and control circuitry 406. Busses 408 couple the components of the controller 400 together to permit the exchange of signals, data, and information from one component of the controller 400 to another. In one example, the control circuitry 406 includes sensor driver circuitry 410 which couples with a parameter sensor 412 (e.g., parameter sensor 122 of FIG. 3) and motor drive circuitry 414 that couples with a drive unit 416 (e.g., e.g. drive unit 108 of FIGS. 1, 2, and 3). The control circuitry 406 also includes an actuator drive circuitry 418, which couples with an actuator 420 (e.g., actuators 116 of FIGS. 1, 2, and 3), and a radio circuitry 422 that couples to a radio 424, e.g., a device that operates in accordance with one or more of the wireless and/or wired protocols for sending and/or receiving electronic messages to and from a peripheral device 426 (e.g., a smartphone). As also shown in FIG. 7, memory 404 can include one or more software programs 428 in the form of software and/or firmware, each of which can comprise one or more executable instructions configured to be executed by the processor 402.

This configuration of components can dictate operation of the controller 400 to analyze data, e.g., information encoded by the signals from parameter sensor 412 and/or drive unit 414, to identify appropriate changes to the diffuser vanes and/or other changes to other operating properties (e.g., motor speed) of the compressor device. For example, the controller 400 can provide signals (or inputs or outputs) to speed up and slow down the drive unit 416, change the diffuser vanes from the first position to the second position, and/or actuate other devices that change the operation of the compressor device (e.g., compressor device 100 of FIGS. 1, 2, and 3).

The controller 400 and its constructive components can communicate amongst themselves and/or with other circuits (and/or devices), which execute high-level logic functions, algorithms, as well as executable instructions (e.g., firmware instructions, software instructions, software programs, etc.). Exemplary circuits of this type include discrete elements such as resistors, transistors, diodes, switches, and capacitors. Examples of the processor 402 include microprocessors and other logic devices such as field programmable gate arrays (“FPGAs”) and application specific integrated circuits (“ASICs”). Although all of the discrete elements, circuits, and devices function individually in a manner that is generally understood by those artisans that have ordinary skill in the electrical arts, it is their combination and integration into functional electrical groups and circuits that generally provide for the concepts that are disclosed and described herein.

The structure of the components in the controller 400 can permit certain determinations as to selected configuration and desired operating characteristics that an end user convey via the graphical user interface or that are retrieved or need to be retrieved by the device. For example, the electrical circuits of the controller 400 can physically manifest theoretical analysis and logical operations and/or can replicate in physical form an algorithm, a comparative analysis, and/or a decisional logic tree, each of which operates to assign the output and/or a value to the output that correctly reflects one or more of the nature, content, and origin of the changes that occur and that are reflected by the inputs to the controller 400 as provided by the corresponding control circuitry, e.g., in the control circuitry 406.

In one embodiment, the processor 402 is a central processing unit (CPU) such as an ASIC and/or an FPGA that is configured to instruct and/or control operation one or more devices. This processor can also include state machine circuitry or other suitable components capable of controlling operation of the components as described herein. The memory 404 includes volatile and non-volatile memory and can store executable instructions in the form of and/or including software (or firmware) instructions and configuration settings. Each of the control circuitry 406 can embody stand-alone devices such as solid-state devices. Examples of these devices can mount to substrates such as printed-circuit boards and semiconductors, which can accommodate various components including the processor 402, the memory 404, and other related circuitry to facilitate operation of the controller 400.

However, although FIG. 7 shows the processor 402, the memory 404, and the components of the control circuitry 406 as discrete circuitry and combinations of discrete components, this need not be the case. For example, one or more of these components can comprise a single integrated circuit (IC) or other component. As another example, the processor 402 can include internal program memory such as RAM and/or ROM. Similarly, any one or more of functions of these components can be distributed across additional components (e.g., multiple processors or other components).

Moreover, as will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. Examples of a computer readable storage medium include an electronic, magnetic, electromagnetic, and/or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms and any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language and conventional procedural programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Accordingly, a technical effect of embodiments of the systems and methods disclosed herein is to position the diffuser vanes in locations at which, in one example, the compressor device consumes the least amount of power.

As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. A system, comprising: a compressor device comprising an impeller, a drive unit coupled to the impeller, and a diffuser vane in flow connection with the impeller; and a controller coupled to the compressor device, the controller comprising a processor, memory, and executable instructions stored on memory and configured to be executed by the processor, the executable instructions comprising instructions for: receiving a first signal encoding a first value for an operating parameter for the compressor device with the diffuser vane in a first position; receiving a second signal encoding a second value for the operating parameter of the compressor device with the diffuser vane in a second position; comparing the first value and the second value; selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; and generating an output encoding instructions to move the diffuser vane from the second position by the increment.
 2. The system of claim 1, wherein the operating parameter comprises an input power value for the drive unit.
 3. The system of claim 1, wherein the operating parameter comprises a power transmission value that measures torque applied to the impeller by the drive unit.
 4. The system of claim 3, further comprising a torque coupling secured to at least one of the impeller and the drive unit, wherein the first signal and the second signal encode data collected by the torque coupling.
 5. The system of claim 1, wherein the operating parameter comprises a head pressure for the compressor device.
 6. The system of claim 5, further comprising a pressure sensor disposed proximate an output of the compressor device, wherein the first signal and the second signal respecting data collected by the pressure sensor.
 7. The system of claim 1, further comprising instructions for determining an inlet flow value upstream of the diffuser vane and setting the first position to correspond with the inlet flow value.
 8. The system of claim 5, further comprising a flow meter disposed upstream of the diffuser vane, the flow meter providing a third signal that encodes the inlet flow value.
 9. The system of claim 1, wherein the increment changes the position of the diffuser vane in a first direction if the second value is larger than the first value, wherein the increment changes the position of the diffuser vane in a second direction if the second value is smaller than the first value, and wherein the first direction is different from the second direction.
 10. The system of claim 1, further comprising comparing the second value to a threshold criteria, wherein the threshold criteria defines a maximum value for the operating parameter and a minimum value for the operating parameter, and wherein the increment changes the position of the diffuser vane if the second value is equal to or greater than the maximum value and equal to or less than the minimum value.
 11. The system of claim 1, further comprising an actuator coupled to the diffuser vanes, wherein the actuator moves the diffuser vane in response to the output from the controller.
 12. The system of claim 11, wherein the increment defines an angular offset of the diffuser vane from the second position.
 13. A compressor device, comprising: a drive unit; an impeller coupled to the drive unit; a diffuser assembly in flow connection with the impeller, the diffuser assembly comprising an actuator and a diffuser vane coupled to the actuator; and a controller coupled with the actuator, the controller comprising a processor, memory, and executable instructions stored on memory and configured to be executed by the processor, the executable instructions comprising instructions for: receiving a first signal encoding a first value for an operating parameter for the compressor device with the diffuser vane in a first position; receiving a second signal encoding a second value for the operating parameter of the compressor device with the diffuser vane in a second position; comparing the first value and the second value; selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; and generating an output encoding instructions to move the diffuser vane from the second position by the increment.
 14. The compressor device of claim 13, further comprising a parameter sensor coupled with the controller, wherein the parameter sensor is in position to measure the operating parameter, and wherein the parameter sensor generates the first signal and the second signal.
 15. The compressor device of claim 14, wherein the parameter sensor comprises a flow meter upstream of the impeller.
 16. The compressor device of claim 14, wherein the parameter sensor measures input voltage on the drive unit.
 17. The compressor device of claim 14, wherein the parameter sensor comprises a torque meter coupled the impeller.
 18. The compressor device of claim 13, wherein the diffuser vane has a rotation axis about which the trailing edge rotates about the leading edge when moving from the first position and the second position.
 19. A controller for controlling operation of a compressor device, the compressor device having a diffuser vane with a first position and a second position that is different from the first position, said controller comprising: a processor; memory; and executable instructions stored on memory and configured to be executed by the processor, the executable instructions comprising instructions for: receiving a first signal encoding a first value for an operating parameter for the compressor device with the diffuser vane in a first position; receiving a second signal encoding a second value for the operating parameter of the compressor device with the diffuser vane in a second position; comparing the first value and the second value; selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; generating an output encoding instructions to move the diffuser vane from the second position by the increment.
 20. The controller of claim 19, operating parameter comprises an input power value for the drive unit.
 21. A computer program product for improving efficiency of a compressor device, the computer program product comprising a computer readable storage medium having executable instructions embodied therein, wherein the executable instructions comprise one or more executable instructions for: receiving a first signal encoding a first value for an operating parameter for the compressor device with the diffuser vane in a first position; receiving a second signal encoding a second value for the operating parameter of the compressor device with the diffuser vane in a second position; comparing the first value and the second value; selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; generating an output encoding instructions to move the diffuser vane from the second position by the increment. 